Virus infections which attack mammals, including man, are normally contagious afflictions which are capable of causing great human suffering and economic loss. Unfortunately, the discovery of antiviral compounds is far more complicated and difficult than the discovery of antibacterial and antifungal agents. This is due, in part, to the close structural similarity of viruses and the structure of certain essential cellular components such as ribonucleic and deoxyribonucleic acids. Nevertheless, numerous non-viral "antiviral agents", i.e. substances "which can produce either a protective or therapeutic effect to the clear detectable advantage of the virus infected host, or any material that can significantly enhance antibody formation, improve antibody activity, improve non-specific resistance, speed convalescence or depress symptoms" [Herrman et al., Proc. Soc. Exptl. Biol. Med., 103, 625 (1960)], have been described in the literature. The list of reported antiviral agents includes, to name a few, interferon and synthetic materials such as amantadine hydrochloride, pyrimidines, biguanides, guanidine, pteridines and methisazone. Because of the rather narrow range of viral infections that can be treated by each of the antiviral agents commercially available at the present time, new synthetic antiviral agents are always welcomed as potentially valuable additions to the armamentarium of medical technology.
The cells of mammals produce, in response to virus infection, a substance which enables cells to resist the multiplication of a variety of viruses. The viral-resisting or viral-interfering substances are referred to as "interferons". The interferons are glycoproteins which may differ in their physico-chemical properties, but all exhibit the same biological properties; namely, they inhibit a wide range of unrelated viruses, have no toxic or other deleterious effects on cells, and are species-specific (Lockart, Frontiers of Biology, Vol. 2, "Interferons", edited by Finter, W. B. Saunders Co., Philadelphia, 1966, pages 19-20).
No practical, economical method has yet been developed for the preparation of exogenous interferon for routine clinical use against viral infections. An alternative approach to producing interferon has, therefore, been pursued, which comprises administering to the animal to be protected or treated a non-viral substance which stimulates--or induces--production of interferon in the cells. The interferon produced in this fashion is referred to as "endogenous" interferon.
U.S. Pat. No. 2,738,351 discloses that compounds of the general formula ##STR1## wherein each of R.sub.1 and R.sub.2 may be alkyl, aralkyl, aryl, cycloalkyl, nitro-substituted aryl, halogen-substituted aryl, alkyl-substituted aryl, or alkoxy-substituted aryl, each of X, Y and Z may be oxygen, sulfur or sulfonyl, ALK is straight or branched alkylene of from one to six carbon atoms, and B may be di(lower)-alkylamino, piperidino, morpholino, pyrrolidino, (lower alkyl)-pyrrolidino, N'-alkyl-piperazino or pipecolino, are local anesthetic agents. Additionally, the discussion of alternate synthetic routes (see Col. 1, 11. 57-70, of said patent) discloses intermediates of the above formula wherein B is amino and (lower alkyl)amino. However, none of the compounds specifically enumerate in the disclosure of said patent contain an alkyl R.sub.1 or R.sub.2 larger than n-pentyl. Furthermore, in none of these compounds are both R.sub.1 and R.sub.2 alkyl and both X and Y oxygen.
Insecticidal and miticidal compounds of the formula ##STR2## wherein R.sub.1 and R.sub.2 may each be, inter alia, lower alkylthio; q is 0 to 5; and A may be, inter alia, 1-piperidino or di(lower alkyl)amino are disclosed in Japanese Patent J7-6042-177.